• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.803-806
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• 2020

The body shape measurement method using 3D images has been widely used due to the recent development of 3D measurement cameras and algorithms. Existing 3D imaging devices are expensive devices, and there is a limit to their universalization. Due to the recent spread of inexpensive 3D cameras and the development of various measurement methods, various possibilities are being shown. It is expected to have a great impact on the medical device market that requires accurate data collection. Various medical device products using artificial intelligence are emerging, and accurate data collection is the most important to develop accurate artificial intelligence algorithms. Collection equipment using 3D cameras is expected to act as a major factor in the development of artificial intelligence algorithms using 3D images.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1973-1979
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• 2016

As technologies evolve, diverse 3D measurement techniques using cameras and pattern projectors have been developed continuously. In 3D measurement, high accuracy, fast speed, and easy implementation are very important factors. Recently, 3D measurement using multi-frequency fringe patterns for absolute phase computation has been widely used in the fringe projection profilometry. This paper proposes an improved method to compute the object's absolute phase using the reference plane's absolute phase and phase difference between the object and the reference plane. This method finds the object's absolute phase by adding the difference between the reference plane's wrapped phase and the object's wrapped phase to the reference plane's absolute phase already obtained in the calibration stage. Through this method, there is no need to obtain multi-frequency fringe patterns about new object for the absolute phase computation. Instead, we only need the object's phase difference relative to the reference planes's phase in the measurement stage.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.749-755
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• 2016

A new method for measuring the 3-axis cutting forces of a pick cutter by substituting costly 3-D load cells is proposed in this paper. The proposed cutting force measurement method is capable of estimating the 3-axis cutting forces through mechanical constraints using four single-axis compressive load cells and shoulder bolts. The feasibility of the proposed method was verified by finite element analysis, and the accuracy of the force measurement of the developed force measurement device was investigated by conducting linear rock cutting tests. The tests showed that the new cutting force measurement method is able to measure 3-axis cutting forces with a relative error of approximately 6%. These results imply that the new method could be a suitable alternative to conventional 3-D load cells. In addition, it will allow a significant reduction of approximately 20-30% in the costs required for measuring the cutting force when compared to conventional 3-D load cells.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.599-602
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• 2010

조절반응의 평가는 옵토메트리 검사의 중요한 일부분이다. 본 연구는 조절반응의 타각적인 검사방법인 자동굴절계와 MEM 검영법 및 Nott 동적검영법으로 측정한 검사결과의 상관성과 차이를 비교하고자 하였다. 본 연구의 취지에 동의하는 19~29사이(평균나이 22.22${\pm}$2.43세)의 정상시력을 가진 27명의 대학생을 선정하여 4D(25cm)의 조절자극이 주어진 상태에서 자동굴절계(Shin-Nippon NVision-K 5001)와 MEM 검영법 및 Nott 동적검영법을 실시하여 조절 반응을 측정하였다. 4D의 조절자극에 대한 조절반응은 자동굴절계(Shin-Nippon NVision-K 5001) 3.70${\pm}$0.25D, MEM 검영법 3.58${\pm}$0.30D 그리고 Nott 동적검영법 3.77${\pm}$0.29D로 각각 측정되었다. 3가지 검사는 상호간에 높은 상관성이 있었다(p<0.05). MEM 검영법은 Nott 동적검영법보다 0.19${\pm}$0.13D 더 낮게 측정되었고(p<0.05), 자동굴절계(Shin-Nippon NVision-K 5001) 보다 0.12${\pm}$0.24D 더 낮게 측정되었다(p<0.05). Nott 동적검영법과 자동굴절계(Shin-Nippon NVision-K 5001)로 측정한 값은 유의한 차이가 없었다(p>0.05). MEM 검영법으로 측정한 조절반응은 Nott 동적검영법이나 자동굴절계로 측정한 값보다 더 낮았다. 저자는 조절반응을 평가할 때, MEM 검영법을 제외한 Nott 동적검영법과 자동굴절계(Shin-Nippon NVision-K 5001)는 상호 대체하여 사용할 수 있다고 주장한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.329-330
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• 2011

3D 영상산업이 발전해 오면서 현재 3D 영상으로 가장 많이 사용되는 것이 바로 stereoscopic 영상이다. 이러한 영상은 인간의 뇌를 속임으로써 화면에 비쳐지는 영상이 마치 화면 밖에 위치하는 것 같은 착각을 일으키게 만들어 3D영상을 인식할 수 있게 해준다. 이때 사람이 양안시를 인식하는 문제에 관한 연구는 이미 안경학에서 많은 발전을 이루어 왔지만, 현재 논의의 중점인 3D 양안시력은 평소 사람이 사용하는 양안시가 아닌 3D Display에서 비춰지는 영상을 다양한 방법으로 양쪽 눈에 다른 영상을 인식하게 함으로써 입체를 인식하게 하는 것이며, 이러한 3D 양안시력을 측정하는 방법에 대해서는 기존의 양안시력과는 다른 측정 방법을 적용하여야 한다. 따라서 이 논문에서는 이러한 3D 입체 영상에 대한 입체시를 측정하는 방법에 대하여 제안한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.695-696
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• 2021

최근 다양한 연령층과 직업군들 사이에서 기능성 신발에 대한 관심이 증대되고 있다. 그러나 기능성 신발 및 맞춤형 신발은 높은 가격대와 긴 제작 시간이 필요하다. 이러한 문제점은 3D 스캐너 도입으로 해결이 가능하나, 정확한 발 형상 측정이 가능한 3D 스캐너는 고가의 장비이기 때문에 매장별 보급이 어렵다. 본 논문은 기능성 신발의 보급을 위하여 저가형 3D 스캐너에서 정확한 발 고유 변인을 측정할 수 있는 시스템에 대해 서술한다. 이를 위해 이를 위해 저가형 Depth Camera를 이용한 저가형 3D 스캐너의 발 형상 3D 점군 데이터를 2차원으로 변형하고, 발 형태를 감싸는 최소 사각형(Min Area Rect)를 형성하여 발 안쪽점 및 발 가쪽점을 추정한다. 생성된 최소 사각형과 발 안쪽점 및 발 가쪽점 등은 발 고유 변인 측정의 기준이 된다. 실험 결과에서는 측정 기준을 이용하여 발 고유 변인인 발 길이, 발 너비, 발꿈치 너비, 발꿈치에서 발안쪽점 및 발 가쪽점 길이 등 5가지 고유 변인을 측정하는 것을 보여준다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.391-397
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• 2017

Recently, digital image correlation (DIC) techniques have been used to measure dynamic deformation during tensile testing. The standard tensile test method measures the average displacement of the relevant specimen to calculate the true stress-strain curve. Therefore, the validity of the true stress curve is restricted to the stress incurred within the uniform stretching interval, i.e., the maximum stress corresponds to the starting point of the necking deformation. Alternatively, if DIC is used, the effective range of the strain and strain rate can be extended to the breaking point of the tensile specimen, because of the feasibility of measuring the local strain over the entire area of interest. Because of these advantages, many optical 3D measurement systems have been introduced and used in research and industry. However, the conventional 3D measurement systems are exceedingly expensive and time consuming. In addition, these systems have the disadvantage of a very large equipment size which makes their transport difficult. In this study, a 2D image correction method employing a 2D DIC measurement method in conjunction with a numerical analysis method is developed using a smartphone. The results of the proposed modified 2D DIC method yielded higher accuracy than that obtained via the 3D measurement equipment. In conclusion, it was demonstrated that the proposed 2D DIC and calibration methods yield accurate measurement results with low time costs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.181-181
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• 2004

3 차원 형상측정기술(3-D Profile Measurement Method)은 가공품의 치수검사 및 형상측정 등의 공학분야뿐만 아니라 최근에는 의류산업 및 의학산업은 물론 오락산업의 가상현실 구현 등 여러 분야로 점차 사용이 확대되고 있다. 이러한 요구를 만족시킬 수 있는 광학을 바탕으로 한 비접촉 3 차원 형상측정방법(Non-contacting 3-D Profile Measuring Method)은 고속, 고정밀도 측정이 가능하기 때문에 활발히 연구되고 있다. 광학을 이용한 대표적인 3 차원 비접촉 측정방법의 하나인 영사식 무아레는 그림자식 무아레의 단점인 격자의 크기가 측정물체보다 커야 한다는 점과 측정물체와 격자사이의 거리 제한 문제를 해결하였으며, 위상이동법을 사용함으로서, 무아레 무늬 형태의 영향을 받지 않고 측정이 가능해졌다.(중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.389-392
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• 2016

As technologies evolve, 3D measurement techniques using cameras have been developed continuously. In 3D measurement, high accuracy, fast speed, and easy implementation are very important factors. Recently, 3D measurement using multi-frequency fringes has been widely used. This method is generally a method of measuring the height of a image obtained by projecting a sine wave through the projector. The sine wave is produced by software. However, this sine wave is not a perfect sine wave by gamma of projector. This is given a bad influence on the height measurement, and can not measure the correct height. In this paper, we propose a method for correcting the phase of the sine wave to avoid being affected gamma. Through this method it will be able to make more accurate height measurement.

• The Korean Journal of Nuclear Medicine Technology
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• v.24 no.1
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• pp.33-38
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• 2020

Purpose Vitamin D is essential for maintaining bone health, controling cell proliferation or differentiation, strengthening immune function by controlling calcium metabolism in the body. Vitamin D deficiency can lead to increase the risk of rickets, osteoporosis, cardiovascular disease, diabetes and cancer. Especially, South Korea is one of the highest population proportion of vitamin D deficiency. Accurate determination of levels of 25-OH-VitD or 25-OH-VitD3 in blood serum is required for the diagnosis and treatment of vitamin D deficiency. In this study, radioimmunoassay of 25-OH-VitD and 25-OH-VitD3 was performed and compared to evaluate the effectiveness of Vitamin D radioimmunoassay. Materials and Methods Serum 25-OH-VitD and 25-OH-VitD3 levels were measured using radioimmunoassay. The interrelationship, reproducibility and population distribution rate were evaluated. In addition, the internal quality control was performed at Asan Medical Center from April 2017 to June 2019 and the result of external quality control (Interagency proficiency evaluation) of first and second half of 2018 hosted by the Korean Society of Nuclear Medicine Technology (KSNMT). Both tests were measured by same manufacturer's reagent. Results 25-OH-VitD showed a strong positive correlation on 97 samples, as 25-OH-VitD3 x 0.9 + 0.3 (R>0.9). In repeated measurement, the average Diff(%) value of the reproducibility evaluation of 25-OH-VitD and 25-OH-VitD3 were 7.7% and 7.4%, respectively. Population distribution results showed no statistically significant differences(p>0.05). The resultant value of internal quality control, which measured from April, 2017 to June 2019 in Blood test room of Nuclear Medicine at Asan Medical Center, showed average (CV%) 6.2% and 6.8%, respectively. As a result of the external quality control (interagency proficiency evaluation) Z value obtained under 2.0, as shown below; Conclusion The interrelationship, reproducibility, population distribution rate, internal quality control and external quality control between 25-OH-VitD and 25-OH-VitD3 radioimmunoassay shows superior outcome. Radioimmunoassay, which can be alone measured in the blood as 25-OH-VitD or 25-OH-VitD3, is considered suitable screening tests for the diagnosis of vitamin D deficiency.